Critical orange punch clones

Bud formation is coming along nicely. Temps leaning towards high side,and might be higher for next few days. Very nice weather at the moment, and my hps @600w. Room will run, 2.5c above ambient temperature. Still showing signs of stress on leaf stems. Not convinced its temperature. So will test soil ph today. I suspect its running a little low. Will probably add a couple of pinches of palm ash, to buffer it. Today will be ro water only @ph 7.0. For soil test.